The present invention relates to a method of manufacturing rollers, particularly rollers for roller chains. More particularly, it relates to such a method which includes winding of a metallic band piece on a mandrel so that the ends of the band piece abut against one another and are flush with one another, and heating and hardening the wound band piece advantageously after calibrating of the same.
The following three methods are generally utilized for manufacturing of rollers: cross-cutting of seamless pulled or welded tubes, deep drawing, and winding in accordance with the above-listed manufacturing steps. The winding method is the most favorable in the sense of material economy and labor economy since the wastes in the cross-cutting method are equal to approximately 20% and in the deep-drawing method are equal to approximately 40%. However, the known winding method has the following disadvantage: In dependence upon the dimensions of the roller, a gap is formed, after winding, between the juxtaposed ends of the metallic band piece, which gap is equal to approximately 0.1 mm. During the thermal treatment this gap becomes even larger. In order to reduce or close this gap, the hardened rollers are subjected to an additional treatment, particularly to ball blasting. As a result of the ball blasting, the outer layer of the wound band pieces elongates and the rollers are partially closed. However, the ball blasted rollers have a very high surface roughness whereby they must be polished after blasting.